Semaphore again

[S P <sage_newbie@yahoo.com>]

Hi,

I am working on some semaphore stuff. Just to check that I am doing the right thing I wrote a normal c code using semaphores :

 

Sema_Try.c  

--------------------------------------------------

 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/sched.h>
 #include <asm/semaphore.h>
 #include <linux/slab.h>

 

int main(void)

{

    struct semaphore hold_sem;

 

    sema_init(&hold_sem, 1);

   

    down_trylock(&hold_sem);

 

    return 1;

}

 

---------------------------------------------------------

 

On compilation I get the following output:

 

> gcc -Wall -D__KERNEL__ -I /usr/src/linux-2.4.7-10/include Sema_Try.c

/tmp/ccSdPsrY.o(.text/lock+x): undefined reference to '__down_failed_trylock'

collect2: ld returned 1 exit status

 

 

__down_failed_trylock is the function invoked by _down_trylock in semaphore.c. Could you suggest me something to get over this problem ?

 

Thanks,

SP

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